Re: [PATCH] thunderbolt: Retain host router DP IN resources during suspend

Sanjay R Mehta
2022-02-20T11:58:05Z

On 2/18/2022 7:55 PM, Mika Westerberg wrote:
> On Fri, Feb 18, 2022 at 07:38:23PM +0530, Sanjay R Mehta wrote:
>>
>>
>> On 2/18/2022 4:43 PM, Mika Westerberg wrote:
>>> Hi Sanjay,
>>>
>>> On Fri, Feb 18, 2022 at 01:11:25AM -0600, Sanjay R Mehta wrote:
>>>> From: Sanjay R Mehta <sanju.mehta@amd.com>
>>>>
>>>> All DP resources are released during suspend and while
>>>> resuming back DP IN resource is not available, therefore
>>>> unable to find DP pair to re-establish the DP tunnel.
>>>
>>> It should get plug event for the DP IN adapters once the router comes
>>> back from sleep. Is that not happening here?
>>
>> Yes, plug event is not happening for the DP IN adapter after resume.
>>
>> The DP In resources are put into tcm->dp_resources list as part of host
>> router enumeration. But when it resumes from sleep, there is no plug
>> event happening for DP IN, hence DP IN resource will not be in
>> tcm->dp_resources list.
>
> Right but if I understand the spec correctly you should get a new
> hotplug event for the DP IN adapters once the host router is moved back
> to "enumerated" state. This is how Intel hardware works at least (and
> this is the understanding I have from the USB4 spec too). Do you see
> anything in the log wrt. this when you resume the domain?

Thanks Mika. I'll re-look at this scenario on our system and will check
if anything needs to be taken care of.

Thank you for the valuable input :).

>